If it is desired to also demonstrate the QR code functionality, it is only necessary to uncomment one line and comment out another in the ContentView.swift file of the iOS app (the explanation is provided in the comments).
Additionally, it is important to build in Release mode to use the -O2 optimization!
Whisper.cpp Speech Recognition:
For whisper.cpp add the desired model.bin and model-encoder.mlmodelcto the Resources/models folder in the iOS XCode Project.
How to download an convert a model is explained here.